1. Field of the Invention
The present invention relates to a wiring substrate formed by droplet discharging and a method of manufacturing thereof. The invention further relates to a thin film transistor and a method of manufacturing thereof.
2. Description of the Related Art
Recently, a droplet discharging technique has been applied to the field of a flat panel display, and developed actively. Since a liquid droplet is directly jetted over a substrate, the droplet discharging technique has various advantages in that a mask is not required, the technique is easily applied to a large-size substrate, the material efficiency is high, and the like. Accordingly, the droplet discharging technique has been applied to formation of a color filter and an electrode for a plasma display, and the like.
When a wiring substrate is formed by droplet discharging, a composition including particles in nanometer size is used. Since a thin film formed of the above-mentioned composition is not well-adhered to an underlying thin film, however, the thin film formed of the composition is likely to be separated from the underlying thin film. Therefore, when the wiring substrate including a pattern formed of the composition is subjected to a wet step such as a washing step, which is indispensable for the semiconductor processing, the pattern is likely to be separated from the underlying thin film.
Further, when the composition is jetted through an end of a nozzle, a phenomenon, which is called as the Lenard phenomenon, is caused. The Lenard phenomenon is the one in which a jetted composition is charged positively due to the deviation of electric charge. Therefore, it has been considered that the thin film adhered with the composition is damaged or destroyed due to the positively-charged composition.